In the astro PCI host bridge device, we call pci_register_root_bus()
in the device's instance_init. This is a problem for two reasons
* the PCI bridge is then available to the rest of the simulation
(e.g. via pci_qdev_find_device()), even though it hasn't
yet been realized
* we do not attempt to unregister in an instance_deinit,
which means that if you go through an instance_init -> deinit
lifecycle the freed memory for the host-bridge device is
left on the pci_host_bridges list
ASAN reports the resulting use-after-free:
==1776584==ERROR: AddressSanitizer: heap-use-after-free on address 0x51f00000cb00 at pc 0x5b2d460a89b5 bp 0x7ffef7617f50 sp 0x7ffef7617f48
WRITE of size 8 at 0x51f00000cb00 thread T0
#0 0x5b2d460a89b4 in pci_host_bus_register /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../hw/pci/pci.c:608:5
#1 0x5b2d46093566 in pci_root_bus_internal_init /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../hw/pci/pci.c:677:5
#2 0x5b2d460935e0 in pci_root_bus_new /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../hw/pci/pci.c:706:5
#3 0x5b2d46093fe5 in pci_register_root_bus /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../hw/pci/pci.c:751:11
#4 0x5b2d46fe2335 in elroy_pcihost_init /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../hw/pci-host/astro.c:455:16
0x51f00000cb00 is located 1664 bytes inside of 3456-byte region [0x51f00000c480,0x51f00000d200)
freed by thread T0 here:
#0 0x5b2d4582385a in free (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/qemu-system-hppa+0x17ad85a) (BuildId: 692b49eedc6fb0ef618bbb6784a09311b3b7f1e8)
#1 0x5b2d47160723 in object_finalize /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/object.c:734:9
#2 0x5b2d471589db in object_unref /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/object.c:1232:9
#3 0x5b2d477d373c in qmp_device_list_properties /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/qom-qmp-cmds.c:237:5
previously allocated by thread T0 here:
#0 0x5b2d45823af3 in malloc (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/qemu-system-hppa+0x17adaf3) (BuildId: 692b49eedc6fb0ef618bbb6784a09311b3b7f1e8)
#1 0x79728fa08b09 in g_malloc (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x62b09) (BuildId: 1eb6131419edb83b2178b682829a6913cf682d75)
#2 0x5b2d471595fc in object_new_with_type /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/object.c:767:15
#3 0x5b2d47159409 in object_new_with_class /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/object.c:782:12
#4 0x5b2d477d29a5 in qmp_device_list_properties /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/hppa-asan/../../qom/qom-qmp-cmds.c:206:11
Cc: qemu-stable@nongnu.org
Fixes: e029bb00a7 ("hw/pci-host: Add Astro system bus adapter found on PA-RISC machines")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/3118
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250918114259.1802337-3-peter.maydell@linaro.org>
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